JP2777893B2 - Method and apparatus for injecting pneumatic fuel into cylinders of a reciprocating internal combustion engine - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method of pneumatic fuel injection into cylinders of a reciprocating internal combustion engine and a corresponding carburetor injection device with high efficiency, having one or several cylinders. In the travel agency,
Scavenging the cylinder with fresh air without mixing fuel,
Attempts have been made to inject the atomized liquid fuel into the cylinder independently of the point in time determined by the operating cycle of the engine.

Injection of atomized fuel into the cylinder is provided with a valve whose opening and closing is controlled by a cam, an injector that opens into the cylinder, and a unit that supplies liquid fuel to the injector,
A source of compressed air for atomizing and injecting fuel when the injector is open is achieved.

The cylinder is scavenged by fresh air from the pump chamber. The lower part of the pumping chamber is connected to the cylinder and compresses the air in the pumping chamber as it reaches the bottom dead center as the piston moves down through the cylinder. Two conduits connecting the pump chamber to the cylinder vents pump the compressed air in the pump chamber to the cylinder. As the piston approaches bottom dead center, the vent that was previously blocked by the piston is opened, and compressed air enters the cylinder and scavenges the cylinder.

Using compressed air from the pump chamber to atomize and inject fuel is also one of the proposals. For this purpose, the pump chamber is connected to the injector by a conduit containing a check valve. The portion of the conduit downstream of the check valve may be used as a storage for compressed air, or a separate storage may be provided and connected thereto. When the injector is opened, a certain amount of compressed air is used to atomize the fuel and inject it into the cylinder. When the pressure in the pump chamber approaches the maximum value, the check valve is opened and the compressed air reservoir is refilled.

Such devices that do not require a separate compressed gas source include:
However, a connecting conduit for connecting the pump chamber and the injector is required. Optionally, this conduit is also connected to a compressed air storage.

In the case of fuel-injected engines with several cylinders, it is also proposed to use the atomization of burned compressed gas from one cylinder into another cylinder. The injection takes place at the opening of a valve for injecting fuel-mixed air into the cylinder to fill the other cylinder. The effect of the hot gas extracted from the one cylinder is limited to atomization of liquid fuel by mixing with intake air and injecting into the cylinder when the valve opens the opening, and in some cases, vaporization of liquid fuel Is done.

In this case, unlike the above-described two-stroke engine and an engine similar thereto, fresh fresh air for scavenging is introduced into the cylinder independently of the introduction of fuel, and the fuel itself introduces air into the cylinder. It does not need to be done by a pneumatic injector independent of the device.

In the case of pneumatic injection, it has been mentioned to use an auxiliary compressed air source or to use a connecting conduit connecting between the pump chamber and the cylinder, sometimes a compressed air storage device.

Accordingly, it is an object of the present invention to provide a cylinder having two independent cylinders for scavenging with fresh air without fuel and for injecting liquid fuel atomized by pressurized gas.
In a stroke internal combustion engine, it is a proposal of a method of performing pneumatic fuel injection to one cylinder at a predetermined moment of an operation cycle of the engine, which method does not require an auxiliary compressed air source and has a pump chamber. In the case of an engine, there is no need for connecting means for connecting the pump chamber to the injector.

For this purpose, the gas taken from one cylinder of the engine atomizes the fuel and injects it into the cylinder.

The invention also relates to a device for achieving pneumatic injection of fuel into one cylinder of an engine using gas taken from this cylinder or, if the engine has several cylinders, another cylinder.

To assist in understanding the present invention, some methods will be described with reference to the accompanying drawings, and the operation of the method according to the present invention will be described by means of some embodiments of the injection device. However, these descriptions do not limit the invention.

〔Example〕

FIG. 1 shows one cylinder 1 of a two-stroke engine in which a piston 2 connected to a crankshaft 4 via a connecting rod 3 reciprocates. The open lower portion of the cylinder 1 is connected to the pump chamber 5, and the piston 2 enters a part of the pump chamber 5 and moves toward the bottom dead center. The pump chamber 5 has an intake pipe 7 opened and closed by a check valve 6. Piston 2
Moves toward the bottom dead center, and the pump chamber 5
The compressed air is pumped into a conduit such as 8 and the compressed air flows through a vent 9 into the chamber of the cylinder 1. When the piston 2 moves downwards away from the previously blocked air vent 9, the conduit 8
, Fresh air flows in, and the cylinder 1 is scavenged.

An exhaust pipe 11 is connected to the chamber of the cylinder 1 through the exhaust port 10. The position of the exhaust port is slightly deviated from the position of the vent port 9, so that when the piston 2 moves downward, the exhaust port 10 is opened first, and then the vent port 9 is opened. Fresh air flows into the cylinder 9 to scavenge the cylinder 1, and burned gas is discharged from the exhaust port 10.

The upper part of the cylinder 1 is closed by a cylinder head 12, on which an assembly 14 including a pneumatic injection device 15 and a compressed air storage part 17, which realizes the present invention, and a spark plug 13 are fixed. Have been.

The pneumatic injector, termed “pneumatic injector 15”, includes a fluid fuel supply injector 16.

The pneumatic injector 15 has a chamber 15a formed inside the cylinder head 12 that opens at the top of the cylinder 1 at the position of the valve seat 18 and the valve 20. Valve 20
Is in contact with the drive cam 21.

The valve 20 closes or opens the valve seat 18 and the valve 20 by the operation of the cam 21 and the return spring 32 to open and close the pneumatic injector.

The fuel supply injector 16 supplies fuel to the chamber 15a. This chamber 15a can have a venturi 24. The reservoir 17 is in communication with the injector chamber 15a by a conduit 25. Part of this conduit may be part of the chamber 15a itself, and may include a fuel supply injector 16 and a venturi 24 therein.

As the piston 2 moves downward, as described above, the exhaust port 10 and the vent port 9 are sequentially opened before reaching the bottom dead center. Subsequently, the cylinder is scavenged with fresh air, and the piston 2 reaches the bottom dead center.
Start moving upward as shown in.

After the bottom dead center, the angle α between 10 ° and 50 °,
(More preferably 20 ° to 30 °), the cam 21
Opens the pneumatic injector 15 by pushing down the stem of the valve 20 as shown in FIG. The rotational position of the shaft 21a of the cam 21 can be determined by the position of the piston 2, whereby the degree of opening of the angle α can be adjusted to a desired value.

At the point selected for injection, the gas contained in the reservoir 17, which has an internal pressure which is much higher than the pressure in the cylinder, passes through the venturi 24 and at a very high speed the chamber of the pneumatic injector 15 Penetrate inside.

Since the chamber 15a of the injector 15 is previously filled with the liquid fuel by the fuel supply injector 16, the liquid fuel receives an ultra-high-speed gas and becomes a very fine mist, and is injected into the cylinder from the valve seat 18 portion. Is done. This mist contains very fine fuel droplets in a suspended state, and when the storage unit 17 stores hot gas, it is injected in the form of a jet 26 in the form of a vaporized fuel gas.

The mixture of gas and fuel in the atomized state mixes with the fresh air filling the cylinder, and the fuel-air mixture thus obtained is provided with a vent 9 and an exhaust while the piston 2 rises in the cylinder 1. It blocks 10 and is compressed as the piston rises.

The shape of the cam 21 is designed so that the valve 20 is kept open at the beginning of the compression stroke. The fuel-air mixture pressure in the cylinder increases until it exceeds the pressure in the reservoir 17. Depending on how the injection is adjusted and depending on the layer of fresh air and fuel-air mixture in the cylinder 1, the air or fuel-air mixture penetrates into the reservoir 17 and is filled with high-pressure gas.

When the fuel-air mixture is filled into the reservoir 17, the fuel-air mixture quite naturally contains a much lower proportion of fuel than was contained in the mixture at the time of injection.

Due to the shape and position of the cam 21, at a certain point during the compression stroke of the mixture in the cylinder 1, the valve 22 is re-closed by the force of the spring 22, while the cam 21 is in equilibrium with the chamber of the cylinder 1. The gas pressure in the storage unit 17 is stored, so that in the next cycle, the fuel can be effectively atomized and injected into the cylinder.

After the shape of the cam 21 reaches the bottom dead center, the valve 20 can be designed so that the valve 20 recloses when the crank angle is between 100 ° and 130 °.

The working cycle of the engine is normal for the fuel-air mixture to ignite and burn when the piston reaches its top dead center. As a result, the piston 2 descends again in the cylinder, and the discharge of the burned gas and the scavenging with fresh air are performed again as described above. A second fuel injection using the pressurized gas of the reservoir 17 filled during the previous cycle occurs at A.

A disadvantage of the above-described operating method lies in that the reservoir 17 is filled with a gas containing fuel, whereby the operation using a separate source of compressed air is not performed from the engine cylinder. However, the efficiency of the engine is slightly reduced.

It is also possible to design a cam 21 whose shape is such that the valve opens twice for each revolution of the crankshaft.

With such a cam 21, the valve 20 is first opened once immediately after the cylinder has reached its bottom dead center, whereby, as already mentioned, the pneumatic pressure by the pressurized gas contained in the reservoir 17 An injection is performed. This complex form of the cam 21 is also used during the expansion stroke or during the evacuation of the combustion gas filling the cylinder 1, while the pressure in the cylinder is greater than the pressure in the reservoir 17, during the second stroke of the valve 20. Open. This causes the reservoir 17 to be filled with gas consisting mostly of combustion gases or combustion gases containing a small amount of unburned fuel residues.

The closing of the valve 20 by the rotation of the cam 21 occurs the first time after the injection and before the beginning of the compression stroke in the cylinder, i.e. before the pressure of the fuel-air mixture is still high enough to penetrate the reservoir 17. Then, the valve 20 is kept closed during the entire process of compression, combustion, and expansion. As mentioned earlier, during the expansion stroke or at the beginning of the exhaust,
Also, the valve 20 opens a second time for a short period of time, compared to when it is first opened. At this point, the pressure difference between the cylinder 1 chamber and the reservoir 17 is much higher than during the first opening that caused the injection of the fuel-air mixture, so that the reservoir 17 is now in the cylinder 1 chamber. It is quickly filled by the contained gas in a short time.

In the particular design of the device shown in FIG.
16 may provide discontinuous injection, such as not injecting fuel while the reservoir is being filled.

This allows more effective control of the engine overstroke by reducing the concentration of fuel in the reservoir.

One simple way to implement this mode of operation is to not operate the injector 16 except when the valve 20 is closed.

2 and 3 show the upper part of a cylinder 30 of a two-stroke engine with an injection device 31 having a differently shaped upper part than the upper part of the device 14 shown in FIG.

The pneumatic injector 32, which opens at the top of the cylinder 30, has a valve 33 driven by a cam 34, as before.
It includes a liquid fuel supply means (not shown) and a means 35 for supplying pressurized gas to the pneumatic injector 32 to enable atomization and injection of the liquid fuel.

The means 35 has one end connected to the chamber of the cylinder 30 with one orifice 37 located above the exhaust and vent of the cylinder (not shown) and the other end at the top of the cylinder, Pneumatic injector 32
And a conduit 36 which is connected to the first chamber. The conduit 36 is fitted with a check valve 38 which allows the conduit to be
It is divided into an upstream part connected to 30 and a downstream part connected to the injector 32. The check valve 38 opens when the differential pressure between the upstream side and the downstream side in the conduit 36 exceeds a certain value required to operate the check valve 38.

Downstream of conduit 36 is a pneumatic injector
This constitutes a pressurized gas storage connected to the 32 chambers. Also, this downstream portion of conduit 36 may be connected to a separately mounted reservoir for storing pressurized gas.

Hereinafter, the operation of the injection device according to the second embodiment will be described with reference to FIGS.

In FIG. 2, piston 30a is moving upward in cylinder 30 to compress the fuel-air mixture at the top of the cylinder. The piston 30a closes the orifice 37, and at this time, the check valve 38 is closed because the pressure difference between the upstream and downstream is low.

In FIG. 4, the hatched lines plot the pressure of the gas contained in the cylinder as a function of the volume occupied by the gas and represent the operating cycle of the engine. The operating point of the engine draws a curve 40 that limits the lower side of the cycle when the piston moves upward, and a curve 41 that limits the upper limit of the cycle when the piston 30a moves downward.

At the end of the compression stroke, piston 30a has reached its top dead center and volume V is at a minimum. Ignition, and then combustion, occurs during compression. The pressure in the cylinder reaches its maximum shortly thereafter and the piston descends.

When the upper part of the piston 30a reaches the level of the orifice 37 (FIG. 3), the gas volume in the cylinder becomes the value V0 and the pressure of this gas becomes P2. The operating point of the engine corresponds to point A in FIG. When the check valve 38 is opened and the gas trapped in the chamber of the cylinder 30 fills the conduit 35, the portion of the conduit 35 downstream of the check valve, which serves as a pressurized gas storage, is also provided. To charge.

This is because the pressure in the downstream portion of the conduit 35 is lower than P2 when the orifice 37 is opened, as will be described later.

The piston 30a keeps descending and opens the exhaust port. The pressure in the cylinder chamber decreases during the exhaust and scavenging strokes. The check valve 38 closes rapidly when the pressure falls below P2. By closing the check valve 38, a gas reservoir having a pressure almost equal to P2 is formed.

After the piston 30a passes through the bottom dead center, it rises again in the cylinder. The operating point in FIG.

Before the compression starts, the cam 34 is connected to the valve of the injector 32.
Open 33. (Operating point I). Liquid fuel is supplied to conduit 35 and / or
Alternatively, the gas at the pressure P2 contained in the storage section downstream from the check valve 38 is atomized and injected into the upper part of the cylinder 30. Pneumatic injectors can be designed to close fairly quickly. The closing timing is determined as a function of the cam 34 by design or adjustment of the engine. At this time, the pressure downstream of the check valve is lower than P2.

Next, the fuel mixture contained in the cylinder is
Compressed by 30a. The upper part of the piston 30a closes the orifice 37 at the beginning of the compression stroke (point B in FIG. 4). The volume of gas remaining in the cylinder is V0, and the gas pressure at this time is V0
P1. As can be seen from the diagram of FIG.
P1 is much lower than P2. The pressure in the conduit 35 upstream of the check valve 38 also becomes P1, which is lower than P2. This position of the piston 30a is shown in FIG.

The condition for the injection is that the pressure on the downstream side of the check valve 38 has a value of P3 between P2 and P1.

Otherwise, if the tube 36 has released enough gas during injection to a pressure below P1, a check valve
38 opens during the compression stroke, causing the pressure in conduit 36 to approach P1 as the piston rises and covers orifice 37. The subsequent process is the same as in the previous case.

The check valve 38 remains closed until the operating point returns to A. When the piston 30a opens the orifice 37 (in the state of FIG. 3), the upstream portion of the pipe 35 is at a pressure P2 higher than P3. The check valve 38 opens, and the downstream part of the pipe 35 forming the injection gas storage part is filled with the combustion gas at the pressure P2.

FIG. 5 shows two cylinders of a two-cylinder two-stroke engine.
The upper part of 40c and 41c is shown. The cylinder 40c is equipped with a pneumatic injector 42, which includes a pneumatic injector, the / injector chamber opening at the top of the cylinder 40c at the location of the valve seat of the injector valve 43. The injector 42 also includes a liquid fuel supply (not shown) and a conduit 45 which communicates the top of the chamber of the cylinder 41c with the chamber of the pneumatic injector 42 of the cylinder 40c. .

The pistons 41a of the cylinder 41 in the expansion stroke are lowered when the scavenging is finished and the pneumatic injection is about to be driven by the opening of the valve 43 before the scavenging is finished and the compression in the cylinder 40c is started. The orifice 44 is opened and the conduit 45 connected thereto is designed to cause a shift in the operating cycle of the two cylinders such that a passage from the combustion chamber of the cylinder 41c to the injector of the cylinder 40c is created. ing. At this time, the gas in the cylinder 41c is in a pressure state much higher than the gas pressure in the cylinder 40c.
Fuel is atomized and injected into the cylinder 40c by the pressurized gas in the chamber 41c.

FIG. 5 shows the cylinder 40c immediately before fuel injection into the cylinder 40c, when the orifice 44 of the cylinder 41c is opened due to the downward movement of the piston 41a closing it.
The cylinder 41c has a fuel injection device 46 similar to the device 42 of the cylinder 40c, and a conduit 47 for supplying pressurized gas to the device has a cylinder 41c connecting the cylinders 40c and 41c. To a cylinder with a working cycle shift similar to the shift between

FIG. 6 shows another embodiment of the injection device 32 shown in FIGS. Elements in FIGS. 2 and 3 and corresponding elements in FIG. 5 are indicated by the same numbers, but only the elements on the side of FIG. 6 are indicated by dashes (').

The injection device 32 'comprises a conduit 36' similar to the conduit 36 of the device shown in FIGS. 2 and 3, one end of which is connected to the lower chamber of the cylinder 30 'through an orifice 37' and the other end of which is connected to the chamber of the injector. Connect the injector
The chamber communicates with the upper part of the cylinder 30 'via a valve 33'. A non-return valve 38 'is contained within the tube 36' and divides the conduit 36 'into an upstream section leading to the orifice 37' of the cylinder 30 'and a downstream section leading to the pneumatic injector.

Upstream of the non-return valve 38 ', the conduit 36' connects via a line 50 and a non-return valve 51 to a fresh source of outside air, which may consist of the atmosphere. The inlet of the check valve 51 has a fresh outside air introduction part.

When the cylinder 30 'is scavenged during the exhaust stroke of a two-stroke engine, the pressure in the chamber of the cylinder 30' is reduced by the exhaust wave effect. This pressure reduction opens the check valve 51 and fresh outside air enters the cylinder 30 from upstream of the conduit 36 'to assist in scavenging.

The process and apparatus according to the invention offer in each case the advantage that the pressurized gas produced in the engine can be used for atomization and injection of the fuel. This pressurized gas can be brought close to where it is used to inject fuel into the cylinder and introduced. Further, since the pressure of this gas becomes extremely higher than the cylinder internal pressure during the injection stroke, the quality of atomization and injection of the fuel is improved accordingly. Further, by mainly using the combustion gas for the injection, the power loss of the engine can be suppressed to a low value.

The invention is not limited to only the embodiments described above.

In particular, the use of various types of injectors, pressurized gas storages having various relative positions with respect to the injector and the cylinder, and various shapes of injector driving cams can be considered.

The present invention can be applied not only to a two-stroke engine but also to all reciprocating internal combustion engines of a type in which the introduction and scavenging of fresh outside air and the pneumatic injection are performed independently.

The use of automatic valves, such as check valves, rotary plug valves, or solenoid valves, instead of valves 20, 33, 43, 46, or 33 'does not fall outside the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a conceptual front sectional view of a two-stroke engine including a pneumatic injection device according to a first embodiment of the present invention. 2 and 3 are partial sectional front views of a cylinder portion of a pneumatic injection device according to a second embodiment of the present invention, showing different states of an operation cycle. FIG. 4 shows the second and third
FIG. 4 is a diagram showing an operation diagram of an engine having the cylinder shown in FIG. FIG. 5 is a conceptual front sectional view showing a part of two cylinders in a multi-cylinder period having a plurality of cylinders according to a third embodiment of the present invention. FIG. 6 shows a fourth embodiment according to the present invention.
It is a conceptual front sectional view showing a part of cylinder of an internal-combustion engine containing an injection device of an example. 1.30, 30 ', 40c, 41c Cylinder 2.30a, 40a, 41a Piston 3. Connecting rod 4. Crankshaft 7. Intake pipe 11. Exhaust pipe 13. Spark plug 15.31 …… Vaporization injection device 16. …… Injector 17. …… Reservoir

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-182474 (JP, A) JP-A-62-182473 (JP, A) JP-A-57-13269 (JP, A) JP-A 51-182 74107 (JP, A) JP-A-57-191451 (JP, A) JP-A-63-124860 (JP, A) JP-A-63-88262 (JP, A) JP-A-2-500925 (JP, A) Japanese Utility Model Showa 56-124266 (JP, U) Japanese Utility Model Showa 63-92076 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02M 67/00 F02M 67/04-67/06

Claims (12)

(57) [Claims] At least one cylinder (1,30,30 ', 40)
C) pneumatically injecting fuel into a cylinder of a reciprocating internal combustion engine having the steps of scavenging the cylinder with fresh fuel-free air and removing gas from any one of the cylinders. The liquid fuel is atomized by the pressurized gas containing the one cylinder (1, 30, 30 ', 40).
C) injecting at a predetermined time into the cylinders at different times in one working cycle, so that the withdrawal of gas from the cylinder is performed between the pressurized gas reservoir (17) and the cylinder. The valve means (20) for opening and closing the passage between the first time for vaporizing and injecting fuel into the cylinder by the pressurized gas and the pressurized gas in the cylinder during the compression stroke. A method characterized in that it is performed by opening twice in the same operating cycle as the second time for refilling the reservoir of pressurized gas (17). 2. The method according to claim 1, wherein the pressurized gas is taken from a cylinder where the pneumatic injection takes place. 3. The method according to claim 2, wherein the pressurized gas is taken from an opening in the cylinder near the valve seat through which the injection takes place. 4. The pressurized gas is taken from an opening (37) formed in a part of an inner wall surface of a cylinder (30) which is opened and closed by sliding of a piston (30a). The method described in. 5. The method according to claim 1, wherein the pressurized gas is taken from a cylinder (41c) different from a cylinder (40c) for pneumatically injecting the gas. 6. At least one cylinder (1, 30, 30 ', 40
c) and a pneumatic injection device (41, 31, 42) for injecting fuel into a cylinder of a reciprocating internal combustion engine having a means for scavenging the cylinder with fresh air not containing fuel, said device comprising: A chamber (15a) connected to a cylinder and an injector (15) for supplying liquid fuel, and means for supplying a pressurized gas to the chamber for atomizing the liquid fuel and injecting the liquid fuel into the cylinder; The pressurized gas supply means,
A valve means (zu) for opening and closing the chamber with respect to the cylinder, and two times during one working cycle with the valve means, i.e. the first time when fuel is injected into the cylinder prior to the cylinder compression process; Means for controlling to open when the chamber is filled with gas pressurized during the inflation process. 7. The device according to claim 6, wherein the means for supplying pressurized gas for injecting fuel into the device comprises an opening in a portion of the cylinder (1). An apparatus comprising a pressurized gas storage (17) connected to the other end of a chamber (15a) connected to the cylinder at a position of a valve seat (18) of a valve to be opened and closed. 8. A device according to claim 6, wherein means for supplying pressurized gas to said device (31) is located at one end on the inner wall surface of said cylinder (30) and is opened and closed by sliding of a piston (30a). A conduit (36) connected to the cylinder by an opening (37) through which the fuel gas mixture is injected into the cylinder at the other end, and a check valve (38) in the conduit. Means (35), said valve connecting said conduit with said opening (37) from said valve.
The valve can be divided into an upstream portion up to the one end connected to the cylinder and a downstream portion from the valve to the other end, and the valve can be displaced in the downstream direction and opened by a pressure difference between the upstream and downstream portions. An apparatus characterized by the above. 9. An apparatus according to claim 8, wherein a conduit (50) and a check valve (51) for connecting to a gas source for scavenging the upstream part in the middle of the conduit (36) of the upstream part. And a device for connecting 10. The apparatus according to claim 6, wherein a pneumatic injection device (42) communicating with the chamber of the first cylinder (40) has at one end a chamber of the second cylinder (41c) and an inner wall surface of the cylinder. Conduit (4) connected by an opening (44) drilled in the first cylinder (40C) and connected at the other end to the chamber of the injection device (42) communicating with the chamber of the first cylinder (40C).
5) An apparatus characterized by including: 11. Apparatus according to claim 6, wherein the apparatus comprises a discontinuously operating fuel injector (16). 12. The apparatus according to claim 11, wherein the fuel injector operates only when (16) the valve (20) is closed.